Anxiety and aggression have a large number of adverse effects on individuals, the school and the society at large and are therefore often at the forefront of discussions held by researchers, experts and practitioners alike. The aim of this publication is to aid in efficient prevention and reduction of anxiety- and aggression-related problems. Prevention strategies have been devised on the basis of a theoretical review of factors and trends related to anxiety and aggression. The theoretical parts of the publication are combined with the empirical parts, thus addressing anxiety and aggression in a comprehensive way. The publication addresses anxiety and aggression within the school environment, where children and adolescents spend the majority of their time (in addition to their homes), which makes the school environment an important developmental factor, also when it comes to the development of anxiety and aggression. We hope the publication will prove helpful for anyone who dealswith anxiety- and aggression-related problems on a daily basis, for the purposes of which guidelines for schools have been included in each chapter.